Robinson DW, Brown K, McMenemy M, et al. Datura quids at Pinwheel Cave, California, provide unambiguous confirmation of the ingestion of hallucinogens at a rock art site. Proc Nat Acad Sci USA. December 8, 2020;117(49):31026-31037. doi: 10.1073/pnas.2014529117.
Archaeologists, especially in California (CA), have debated whether ancient rock art sites (RAS) are linked with hallucinogen use. Hallucinogenic plants are depicted at RAS and in ancient relics, e.g., pots and baskets, but until this report, there has been no solid evidence of hallucinogen use at any RAS in the world. Some have argued that south-central CA rock paintings are self-portraits or visions of shamans using hallucinogens, and that RAS "owned" by shamans were avoided by other people. However, most RAS in the area are at habitation sites which are openly accessible. Analysts also suggest that pictographs are not shamanic visions, but images from myth, personifying insects, animals, plants, the sun, etc. There is strong evidence of hallucinogen use, e.g., sacred thornapple (ST; Datura wrightii [Solanaceae]), in Native CA. ST's trumpet-shaped flowers unfurl in a five-pointed "pinwheel" manner. At RAS Pinwheel Cave (PC) in south-central CA, a red pinwheel figure identified as a ST flower is centered in the ceiling. These researchers report evidence of ST use at Pinwheel Cave, with concomitant use of Pinwheel Cave and an associated food processing bedrock mortar complex for other purposes.
Datura spp., with tropane alkaloids atropine and scopolamine, are used as hallucinogens worldwide. In Native CA, ST root infusion (toloache) was used in youth initiations. In some groups, this rite included making sand paintings illustrating cosmological themes. Visions induced by toloache were not used in these paintings. ST was used by adults to gain physical or supernatural power, combat negative powers or ghosts, see the future, find lost objects, or treat various ailments, e.g., as a wound poultice. It was taken before hunting to boost game-finding acuity and energy. It was ingested by eating flowers or seeds, or chewing roots or other parts, as well as in toloache. Given these methods, the absence of morphologically identifiable fragments at Pinwheel Cave and bedrock mortar was not surprising.
Quids are mashed, matted clumps of plant fibers often seen in archaeology. They can be the dry remains of ST, agave (Agave americana, Asparagaceae), yucca (Yucca spp., Asparagaceae), tule (Schoenoplectus californicus, Cyperaceae), tobacco (Nicotiana tabacum, Solanaceae), and other plants that were processed to extract nutrients or stimulants. In a "very unusual" finding, Pinwheel Cave's ceiling has ≥ 56 quids in crevices. Shreds found across the ceiling indicate it may once have held many more, in crevices lost to erosion. Three-dimensional (3D) digital microscopy was used on 15 quids from eight crevices, each crevice containing 1-10 quids, to determine whether they had been chewed. 3D and heat map imaging showed each quid to have one large depression on both top and bottom surfaces. Geometric morphometric methods (GMM) shape analysis found high homogeneity of quids, suggesting similar means of production.
While their fibrous nature precluded preservation of tooth marks, "each quid... had been bilaterally compressed...; the most parsimonious explanation is that [this occurred] between the occlusal surfaces of the upper and lower dentition, with masticatory loading (bite force) causing... depressions." Four of the 15 quids were analyzed via liquid chromatography-mass spectrometry (LC-MS) for atropine and scopolamine. Both alkaloids were "firmly established" in quids analyzed, albeit at low levels. Different quids had different levels of each alkaloid, an expected result since plant content varies by many factors. While the alkaloids' presence supported the theory that quids were composed of ST, other plants could have contributed. Scanning electron microscopy (SEM) was used for genus-level identification of the 15 quids sampled. Fourteen, including the four used in LC-MS, were confirmed as ST; one, yucca. SEM images were consistent with GMM analysis.
Archaeological and palaeobotanical investigation found evidence of food preparation (nuts, seeds, fruits, and game meats), cooking, eating, and projectile point-making and tool maintenance at both sites and both inside and outside Pinwheel Cave. At Pinwheel Cave, remnants of five wetland taxa indicate that basketry or weaving may have occurred, or supplies may have been stored and dried there. Taxa used as tinder were recovered. Evidence of such varied activities stands against the theory of shamanic exclusivity of RAS.
Besides the ceiling pinwheel, other ephemeral red pigments applied at apparently different times in Pinwheel Cave form a circle, unidentified pictograph fragments, and, most interestingly, a "Transmorphic" figure with antennae, dichoptic eye orbits, and a long, slender body with four appendages, each with three finger- or toe-like appendages. Similar figures are seen at other RAS, tentatively identified as shamanic self-portraits or representations of supernatural or even alien beings. These authors argue convincingly that the figure represents instead the sphinx or hawk moth, a major pollinator of Datura spp., commonly seen near ST flowers when they open at night. Botanists report moths "behaving erratically" after sipping ST nectar, "as if intoxicated."
The authors suggest that its significance at Pinwheel Cave in conjunction with the central pinwheel is an instructional reminder of the effects of ST consumption.* The pictographs establish Pinwheel Cave as a space where ST use was appropriate but did not preclude other activities, although seasonal use variations are likely. The radiocarbon record at Pinwheel Cave and bedrock mortar indicates occupation from ~1300-1782 CE, with the earliest quid used in this study dated at ~1530-1655. The last date of occupation was ~1715-1890. The latest dated quid was deposited in 1680-1865. Glass and iron-drilled beads at both sites were available in the region after the establishment of Spanish missions beginning in 1782. A wire-wound bead and two percussion caps show that use continued into the American Period, beginning in 1848. Evidence in this rich report supports an association of hallucinogen use and RAS in the western United States concomitant with varied group subsistence activities.
*Modern psychedelic voyagers may understand that at times it is useful to be reminded, "You took (that drug), remember? You are hallucinating. It's OK."